# thao

Most popular questions and responses by thao
1. ## Chemistry

The value of delta H for the reaction below is -1107kj. 2Ba (s) + O2 (g) -> 2BaO (s) How many kJ of heat are released when 5.75 g of BaO (s) is produced? Here is how I approached this problem: 1. Converted 5.75 g of BaO to mol: 5.75g x (1mol BaO/153.3g

2. ## Chemistry

A 500 mL metal cylinder holding 0.100 moles of helium gas is known to rupture at a pressure of 10 atmospheres. At what temperature, in °C, will the container fail? Here is what I came up with: T= (1.00mol x 0.0821 LxATM/KxMOL) / 10atm x 0.5L =0.01642K

3. ## Chemistry

Ideal gas law question A 4.0 liter container has two gases inside, neon and argon. It is known that at 18 °C, the total pressure of the combined gases is 0.850 atm. If it is known that there are 0.100 moles of neon in the container, how many moles of

A little aluminum boat (mass of 14.50g) has a volume of 450.00cm3. The boat is placed in a small pool of water and carefully filled with pennies. If each penny has a mass of 2.50g, how many pennies can be added to the boat before it sinks?

5. ## Chemistry

How many joules of heat are needed to heat 25.0 g of ice at -5.0 degrees celcius to a final temperature of 40.0 degrees celcius? The specific heat of ice is 2.1 j. Our teacher mention to consider the state of water present at 40.0 degrees celcius which is

6. ## Chemistry

How many grams of ice are needed to cool 250 ml of water from 75 degrees celcius to 5 degrees celcius?

7. ## Physics

A gas is confined in a 0.47-m-diameter cylinder by a piston, on which rests a weight. The mass of the piston and weight together is 150 kg. The atmospheric pressure is 101 kPa. (a)What is the force (in Nt) exerted on the gas by the piston, the weight and

8. ## Chemistry Lab

If 12.50 mL of 0.324 M HCl is diluted to 250.00 mL, what is the concentration of HCl in the final solution?

9. ## Chemistry

Write a balance ionic and net equation for the following: KOH + HC2H3O2 I came up with the following but think this is wrong: KOH + HC2H3O2 -> H2O (l) + KC2H3O2 (aq)

10. ## Chemistry

If a certain gas has a density of 2.34 g/L at 27.0C and 742 torr, what is the molar mass of this gas? I am not sure what formula to use to solve this problem.

11. ## Physics

A box is given a push so that it slides across the floor. How far will it go, given that the coefficient of kinetic friction is 0.16 and the push imparts an initial speed of 4.2 m/s?

12. ## Science

Calculate the density of bromine if 586g of the substance occupies 188mL

13. ## Chemistry Lab

You need 123 mL of 0.245 M NaOH solution for a certain experiment, and the only solution available in the lab is 1.252 M. How many mL OF THE 1.252 M NaOH would you need?

14. ## 8th grade Social Studies

Which colony was the first to promote religious tolerance?

15. ## Chemistry

100 ml graduated cylinder containing 50 ml of water, drop 100g piece of brass into the water what height does the water rise in the graduated cylinder?

16. ## 8th grade Social Studies

How might the colony of Georgia have been different if Oglethorpe's plan had succeeded?

17. ## Chemistry

If the molar volume of an ideal gas is 22.4 L/mol, calculate the theoretical density of hydrogen gas at STP. Not sure what formula to use with this question. Thanks.

18. ## Chemistry

If 12.0 gram of ice are dropped in 150. ml of water at 45 degrees celcius, what is the final temperature of the water?

19. ## Science

At what tempertures is your element a solid, liquid, or gas? Why or how?

20. ## Chemistry

A 25.00 mL sample of seawater taken from a depth of 1000 meters weighs 25.75 g. What is the density of seawater?

21. ## 8th grade Social Studies

Why were slaves in high demand in the southern colonies?

22. ## 8th grade Social Studies

Which colony was the first to promote religious tolerance

23. ## Chemistry Lab

Using the molarity of fromic acid (HCOOH): 0.1033 Calculate the percent by mass of fromic acid in unknown solution. Assume the density of aqueous fromic acid solution is 1.000 g/mL. Need help setting up this problem. Thank you.

24. ## math

A number subtracted from 13is the quotient of -128 and 8 . Find the number. pls help, thxs

25. ## 8th grade Social Studies

Why did more enslaved Africa live in South Carolina than did white settlers?

26. ## Science

At what tempertures is calcium a solid, liquid, or gas?

27. ## Algebra

Write an equation of the line containing the point (o,-4) and perpendicular to the line y=1/3x+5

28. ## math

the minimum size dance floor that the prom committee is considering 30 by 30 . they assume that this size will allow 100 couples to be on the dance floor at once. how many square feet of dance space per couple does this size allow?

29. ## math

the minimum size dance floor that the prom committee is considering is 30 by 30. they assume that this size will allow 100 couples to be on the dance floor at once. how many square feet of dance space per couple does this size allow.

1. ## math

1343.33

posted on September 8, 2017
2. ## math 5

9.34 8.5

posted on September 8, 2017
3. ## Accounting

A. \$6,853

posted on May 21, 2013
4. ## physics

1/2at^2

posted on August 28, 2012
5. ## Chemistry

I came up with this but not sure if it's right: D = 1mol/22.4L x 2.02g/1mol = 0.0902g/L

posted on April 27, 2011
6. ## Chemistry

I recalculated the problem and got it correct. Thank you.

posted on April 25, 2011
7. ## Chemistry

I was giving the answer key with the correct answer at 336 C. Now i'm really confused... Can someone explain.

posted on April 25, 2011
8. ## Chemistry

Makes perfect sense. Thank you.

posted on April 12, 2011
9. ## Chemistry

After some sleep, i was able to come up with the following. It's still not 36 degrees, but close. Can some check my calculation? [mass ice x heat fusion] + [mass melted ice x specific heat water x (Tfinal-Tinitial)] + [mass water x specific heat water x

posted on April 12, 2011
10. ## Chemistry

Filling in the equation, here is what I have. Still not coming up with 36 degrees. Please help: [mass ice x heat fusion] 12.0g x 334j/g [mass melted ice x specific heat water x (Tfinal-Tinitial)] 12.0g x 4.18j/g x 45 (Delta T is 45 because temp of ice from

posted on April 12, 2011

n=174.2 right? How can you do that?

posted on October 16, 2008
12. ## 8th grade Social Studies

so how about another questions? Can you help me?

posted on September 20, 2008
13. ## 8th grade Social Studies

Section 1: The Southern Colonies

posted on September 20, 2008
14. ## 8th grade Social Studies

yes

posted on September 20, 2008
15. ## 8th grade Social Studies

Analyze Why did more enslaved Africa live in South Carolina than did white settlers?

posted on September 20, 2008
16. ## 8th grade Social Studies

i did but i don't understand that question

posted on September 20, 2008